[DSRP Evidence](https://dsrpevidence.org/)

# Global estimation of bankfull river discharge reveals distinct flood recurrences across climate zones

Liu et al., 2026, Nature Communications — Hydrology

Patterns: [Distinctions](https://dsrpevidence.org/pattern/distinctions), [Relationships](https://dsrpevidence.org/pattern/relationships)

## In short

The correct discharge-to-return-period relationship only emerges once rivers are sorted into climate-zone categories rather than treated as one undifferentiated global class.

## What they found (results)

Median bankfull-discharge return periods differ sharply by climate zone (tropical 1.5 yr, temperate 1.8 yr, cold 2.8 yr, arid 4.3 yr), so the standard uniform 2-year assumption overestimates tropical bankfull discharge by up to 54% and underestimates arid discharge by 10%.

## Abstract

Bankfull discharge, the maximum flow a river can convey before spilling over its banks, is central to modelling flood risk and understanding river-channel evolution. Global flood inundation models assume a 2-year return period for bankfull conditions, but this assumption remains untested globally. Here we use observations and machine learning to estimate bankfull discharge at ~1-km resolution along a recently developed global river network. We show that the widely used 2-year discharge reasonably approximates bankfull-flow magnitude, but bankfull return periods vary substantially within and across climate zones. Bankfull conditions occur more frequently in tropical and temperate regions (median return periods of 1.5 and 1.8 years; interquartile ranges of 2.5 and 3.2 years, respectively) and less frequently in cold and arid regions (2.8 and 4.3 years; interquartile ranges of 4.8 and 6.0 years). This variation across climate zones provides a basis for improving the representation of channel capacity in global flood models.

These researchers were not testing DSRP. The finding is theirs; the correspondence to DSRP is drawn by this site.

[Source](https://doi.org/10.1038/s41467-026-76433-3)